Schirmacher W, Ruocco G, Scopigno T
Physik-Department E13, Technische Universität München, Garching, Germany.
Phys Rev Lett. 2007 Jan 12;98(2):025501. doi: 10.1103/PhysRevLett.98.025501. Epub 2007 Jan 9.
A theory for the vibrational dynamics in disordered solids [W. Schirmacher, Europhys. Lett. 73, 892 (2006), based on the random spatial variation of the shear modulus, has been applied to determine the wave vector (k) dependence of the Brillouin peak position (Omega(k)) and width (Gamma(k)), as well as the density of vibrational states [g(omega)], in disordered systems. As a result, we give a firm theoretical ground to the ubiquitous k2 dependence of Gamma(k) observed in glasses. Moreover, we derive a quantitative relation between the excess of the density of states (the boson peak) and Gamma(k), two quantities that were not considered related before. The successful comparison of this relation with the outcome of experiments and numerical simulations gives further support to the theory.
基于剪切模量的随机空间变化，一种关于无序固体中振动动力学的理论[W. 席尔马赫，《欧洲物理快报》73, 892 (2006)]已被用于确定无序系统中布里渊峰位置（Ω(k)）和宽度（Γ(k)）对波矢（k）的依赖性，以及振动态密度[g(ω)]。结果，我们为玻璃中普遍观察到的Γ(k)与k²的依赖性提供了坚实的理论基础。此外，我们推导了态密度过剩（玻色子峰）与Γ(k)之间的定量关系，这两个量之前被认为没有关联。该关系与实验和数值模拟结果的成功比较进一步支持了该理论。
